Short-term effects of nasal pressure support ventilation in acute exacerbation of hypercapnic COPD

Abstract

Background: If nasal pressure support ventilation (NPSV) can be used at the early stage of acute exacerbation of severe COPD, profound ventilatory failure may be prevented without the complication from delayed intubation. To our knowledge, no study has focused on this group of patients.

Methods: In this prospective study, BiPAP was used with three stages of settings each for 30 min as follows: pressure support (PS) 10 cmH2O without PEEP (stage 1), PS 10 & PEEP 5 cmH2O (stage 2), and PS 17 & PEEP 5 cmH2O (stage 3). Data of spontaneous breathing before and after NPSV each for 10 min were also recorded as baselines.

Results: One of our 10 male patients dropped out due to intolerance of the mask, who was intubated immediately. Data of the other nine patients showed that integrated diaphragmatic EMG, respiratory rate, end-tidal CO2, VT/Ti, and VE reduced significantly when compared between baselines and stage 3 values (p = 0.0121, 0.0026, 0.0005, 0.0116, 0.0111 respectively). VT and SaO2 increased significantly (p = 0.0265 & 0.0019). The above parameters showed no significant difference between stage 1 and 2. Maximum inspiratory and expiratory mouth pressure remained unchanged after NPSV. No obvious complication was noted.

Conclusions: For patients with acute exacerbations of sever COPD, early and short-term use of NPSV at higher level of PS can significantly suppress inspiratory muscle activities and respiratory drive, and improve VE, respiratory rate, gas exchange and thoracoabdominal asynchrony. Respiratory muscle strength changes little. The addition of 5 cmH2O of PEEP to 10 cmH2O of PS has no obvious effect.